A WLAN is widely applied in various places. The WLAN includes a radio access point (AP) and a terminal, where the terminal accesses a network using the radio AP. A wireless controller may further be added to the WLAN, to manage the AP.
Enhanced distributed channel access (EDCA) may be used in the WLAN, to provide a priority-based access mechanism. In a network using the EDCA, the radio AP sends an EDCA parameter set element that includes a QoS parameter set to the terminal. The QoS parameter set includes QoS parameters, for different access categories (AC), of the terminal. The ACs include: AC_BE (which means best effort), AC_BK (which means background), AC_VI (which means video), and AC_VO (which means voice). A QoS parameter (that is, an access channel configuration parameter) of each access category includes a minimum size and a maximum size of an exponent form of contention window, a transmission opportunity (TXOP) limitation, and the like. In this way, a different value is set for the QoS parameter of each access category such that some real-time multimedia services (such as services of an AC_VI and AC_VO type) can have more opportunities to access a channel. Therefore, a delay of a real-time multimedia service is reduced, data transmission of the real-time multimedia service is more fluent, and user experience is improved.
A network device (a radio AP or a wireless controller) may generate an EDCA parameter set element based on a set QoS parameter set, and adds the EDCA parameter set element to a beacon frame broadcast to the terminal, an association response frame sent to the terminal, or a probe response frame sent to the terminal. However, the network device cannot dynamically adjust a QoS parameter set of the terminal on a per terminal basis, resulting in low data transmission efficiency and poor user experience.